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PubMed1981

[Experimental traumatic epiphysiolysis (author's transl)].

Two experimental series of epiphysiolysis, with and without displacement, were performed on 100 young rabbits in each group. The histological site of the epiphysiolysis was demonstrated, and the healing process studied. The basic healing process is induced by the vascular metaphyseal penetration of the separation line, as shown in the epiphysiolysis without displacement. A compensative mechanism appears in the series of epiphysiolysis with displacement, consisting of an epiphyseal vascular penetration of the epiphyseal plate, performing then the embryonal anatomical pattern. The vascular epiphyseal channels close progressively after they reach the metaphyseal vessel. If they do not join the metaphyseal vessels quickly enough, or in sufficient number, they are invaded by osteoblastic cells and fibrous or bony bridges will be created through the epiphyseal plate. These bridges are responsible for growth retardation, axial deviation and even early closure of the epiphyseal plate.

Animals↗
PubMed1984

Triplane fractures of the distal tibial epiphysis.

Triplane distal tibial fractures can occur as two-, three-, or four-part fractures with or without a fibular fracture. Diagnosis of the particular anatomy of each fracture is ascertained by plain radiographs; if the fracture is displaced 2 mm or more on any view, anteroposterior and lateral tomograms and, if possible, a limited computerized tomography (CT) scan should be done. A plaster cast in situ for non-displaced fractures or closed reduction for displaced fractures should be attempted first by internal rotation and anterior movement of the fibular metaphyseal piece. Failure to obtain and/or maintain an adequate closed reduction (less than 2 mm displacement), determined by plain radiographs, is an indication for operative treatment. Operative treatment consists of screw fixation for the metaphyseal fragment alone in two-part fractures and both metaphyseal and epiphyseal screw fixation in three-part fractures. Associated fibular fractures may also require internal fixation. The prognosis is generally good if adequate reduction has been achieved by closed or open means.

Adolescent↗
PubMed1984

The fine structure of the proximal growth plate of the avian tibia: vascular supply.

The vascular supply to the proximal tibial growth plate of the 7 weeks old chicken is described using various vascular markers. In addition the ultrastructure of metaphyseal and epiphyseal vessels as well as their supporting tissue is reported. The metaphyseal arterioles terminate in large calibre vessels which have occasional endothelial gaps and no basement membrane or supporting cells, and therefore could be classified as venous sinusoids. In contrast the epiphyseal arteriole terminates in a capillary-venule plexus lined by an attenuated and fenestrated but continuous endothelium. This paper definitively establishes that communication of epiphyseal and metaphyseal vessels across the avian growth plate does not occur. The eosinophilic streaks which often join these two vascular supplies have been described ultrastructurally and would appear to be remnants of the 'retreating' epiphyseal vessels.

Animals↗
PubMed1982

Density of trabecular framework and osteogenic activity in the spongiosa of long bones subjected to drastic changes in mechanical loading in the dog.

In 2 groups of dogs aged from 4 months to 3 years, we estimated the density of the spongiosa and the distribution of osteogenic activity in transverse sections of the metaphyses and epiphyses of the experimentally overloaded or unloaded right radii, together with those of the contralateral control bones. Overloading elicited an increase in the density of the spongiosa framework to a higher degree within the peripheral than the deeper metaphyseal spongiosa or within the epiphyses. Some time after operation, the osteogenic activity appeared reduced through the spongiosa in every district although to a greater extent in the regions in which its more pronounced condensation had occurred, i.e. within the metaphyseal subcortical spongiosa. In the unloaded bones, the density of the spongiosa was markedly reduced compared to the control. The differences in the architectural pattern between subcortical and deeper spongiosa were attenuated. Conversely, osteogenic activity was enhanced in every district, being evenly distributed within the spongiosa framework both in the metaphysis and the epiphysis. From comparison between the results obtained by the 2 sets of experiments it seems reasonable to infer that mechanical stress appreciably stimulates bone mass increase and the ensuing remodelling of the spongiosa architecture; at the same time, the more heavily loaded portions of the framework would be subjected to a lesser degree of structural renewal than that occurring in the spongiosa regions less essential to mechanical resistance. The latter, therefore, would rather perform the function of labile stores of mineral salts.

Animals↗
PubMed1980

The arterial anatomy of the adult human lumbar vertebral body: a microarteriographic study.

The anatomy of the arteries of 93 adult human lumbar vertebral bodies was studied microarteriographically. There is a network of periosteal arteries joining the arteries of adjacent vertebrae on the anterolateral and posterior surfaces. These are prominent between the fourth and fifth lumbar arteries. There are three types of intra-osseous arteries: equatorial, metaphyseal and peripheral. Each supplies a separate zone. The peripheral arteries are short, branch early and have centripetally directed terminal branches; they supply the outer collar of the vertebral body. The equatorial and metaphyseal arteries are morphologically similar, having straight unbranching stems, pre-terminal coils and centrifugal terminal branches. The equatorial arteries supply the central core of the vertebral body subjacent to the nucleus pulposus, and the metaphyseal arteries supply an annular zone between the other two types. Some circumstantial evidence that discal degenerative disease is associated with discal, or vertebral body, anoxia is presented. The present study adds to this evidence.

Adult↗
PubMed1993

Femoral neck preservation in total hip replacement.

Preservation of the femoral neck in hip arthroplasty creates a particular biomechanical situation which is clearly different from what is found even after partial neck removal. The femoral neck consists in fact of a "cylinder of cortical bone" that can be used as the "base" for anchoring the stem to the femur, in contrast to the press-fit procedure or other solutions. The mechanical and biological advantages are as follows: 1) Primary triplanar stem stability, in particular rotational stability. Rotational movements of the stem are blocked by the tough lateral cortical cylinder of the neck. Resistance to varus-valgus stress and collapse is also increased vertically and frontally. 2) Proximal cortical fixation. Primary fixation of the stem is provided by the neck cortex, whereas its mid-distal part is merely held by the metaphyseal cancellous bone and the tip is undersized with respect to the medullary canal. 3) Stress loads distributed along physiological lines of stress. Retention of the neck permits preservation of the trabecular systems, along which the stress is distributed towards the diaphysis and the greater trochanter. 4) Elasticity of the bone-prosthesis system. Most of the stem is contained within the metaphyseal cancellous bone that lies between the prosthesis and the cortical bone, creating a bone-prosthesis module with variable and integrated elasticity. 5) Preservation of the bone-stock. The amount of residual bone following implant of the prosthesis increases, not only because of the presence of the femoral neck, but also as a result of the preservation of most of the metaphyseal cancellous bone. There is therefore greater bone-ingrowth, which is also favoured by the fewer changes in the endosteal blood supply. 6) Prosthesis revision is simpler, since the stem can easily be removed and a second neck resection performed. Our clinical and experimental studies, together with those of Freeman et al., confirm that the femoral neck is present for a long time after implant. Finally, we report a study of 200 prostheses with a follow-up of 1 to 6 years, demonstrating neck reabsorption in only 1% of the cases.

Biomechanical Phenomena↗
PubMed1998

Thanatophoric dysplasia type I: new radiologic, morphologic, and histologic aspects toward the exact definition of the disorder.

A comprehensive seven-step study on THANATOPHORIC DYSPLASIA without cloverleaf skull (TD Type I) was carried out postmortem on three aborted fetuses of 19, 26-27, and 34 weeks and one preterm neonate of 35 weeks gestation, respectively. The characteristic x-ray configuration of the spine in TD Type I presenting with H-, U- or reversed U-shape vertebrae were shown to correlate with the inclination or reclination of the vertebral bodies within a kyphotic or lordotic segment. The bowing of the tubular bones in TD Type I is explained by a diminished mechanical stability that is causally related to a specific cartilage structure. The perichondral spurs are defined by their morphologic structure, and their origin is attributed to a normal perichondral ossification in the presence of an impaired enchondral ossification. Impairment of enchondral ossification was more evident in the periphery than in the center of the metaphyses leading to a tongue-shaped osseous cone directed toward the epiphysis. The perichondral spurs and the linguiform enchondral growth plate resulted in a three-phase maple leaf-like contour of the metaphyses of tubular bones and acetabular roof. The nature of the perichondral fibrous bands, the fibrovascular bundles, and the fibrovascular bands of the growth plate and their significance in atypical ossification processes are discussed in detail. It is suggested that the diminished longitudinal growth of the skeleton is caused by a reduced mitotic activity of cartilage cells in the proliferative zone leading to a reduction of cell numbers in the columnar zone transversely oriented spongiosa bars resulting from desmal ossification of the metaphyseal fibrovascular structures.

Bone and Bones↗
PubMed1998

Parathyroid hormone (1-34) increased total body bone mass in aged female rats.

Daily subcutaneous administration of bovine parathyroid hormone (PTH)(1-34) stimulates bone formation and increases bone mass in rat tibiae, femora and lumbar spine. However, the effects of PTH on the whole body bone mineral content and density determined by dual energy x-ray absortiometry (DEXA) have not been previously reported in rats. Eighteen-month-old intact female rats were subcutaneously injected daily with 0, 40, 80 or 160 micrograms/kg/day of bovine PTH (1-34) for either 15 or 60 days. Whole body DEXA was performed at 1 day before autopsy, and bone area, bone mineral content (BMC) and bone mineral density (BMD) of the total body were determined. Total femoral, tibial and lumbar spine BMD was also determined ex vivo. Cancellous bone histomorphometry was performed on sections of double-labeled proximal tibial metaphyses. Whole body bone mineral content and density were significantly increased by 60 days, but not by 15 days, of PTH treatment at all dose groups compared with vehicle controls. Lumbar vertebral and total femoral BMD was significantly increased at all doses of PTH by 15 days of administration and further increased by 60 days. All doses of PTH increased trabecular bone area in proximal tibial metaphyses by 15 days and further increased by 60 days. All doses of PTH increased trabecular bone area in proximal tibial metaphyses by 15 days and further increased by 60 days. In proximal tibial cancellous bone, dose-dependent increases in percent labeled perimeter, mineral apposition rate and bone formation rate-bone volume referent were found between 40 and 160 micrograms/kg of PTH treatment by 15 days, and no further increases were found by 60 days. Our results showed that in aged female rats, bovine PTH(1-34) increased bone formation and total body bone mass.

Animals↗
PubMed2006

Unburdening evo-devo: ancestral attractions, model organisms, and basal baloney.

Although flourishing, I argue that evo-devo is not yet a mature scientific discipline. Its philosophical foundation exhibits an internal inconsistency that results from a metaphysical confusion. In modern evolutionary biology, species and other taxa are most commonly considered as individuals. I accept this thesis to be the best available foundation for modern evolutionary biology. However, evo-devo is characterized by a remarkable degree of typological thinking, which instead treats taxa as classes. This metaphysical incompatibility causes much distorted thinking. In this paper, I will discuss the logical implications of accepting the individuality thesis for evo-devo. First, I will illustrate the degree to which typological thinking pervades evo-devo. This ranges from the relatively innocent use of typologically tainted language to the more serious misuse of differences between taxa as evidence against homology and monophyly, and the logically flawed concept of partial homology. Second, I will illustrate how, in a context of typological thinking, evo-devo's harmless preoccupation with distant ancestors has become transformed into a pernicious problem afflicting the choice of model organisms. I will expose the logical flaws underlying the common assumption that model organisms can be expected to represent the clades they are a part of in an unambiguous way. I will expose the logical flaws underlying the general assumption that basal taxa are the best available stand-ins for ancestors and that they best represent the clade of which they are a part, while also allowing for optimal extrapolation of results.

Animals↗
PubMed2003

Pavlov's methodological behaviorism as a pre-Socratic contribution of the melding of the differential and experimental psychology.

The differential/experimental distinction that Cronbach specified is important because any adequate account of psychological phenomena requires the recognition of the validity of both approaches, and a meaningful melding of the two. This paper suggests that Pavlov's work in psychology, based on earlier traditions of inquiry that can be traced back to the pre-Socratics, provides a potential way of achieving this melding, although such features as systematic rather than anecdotal methods of observation need to be added. Pavlov's methodological behaviorist approach is contrasted with metaphysical behaviorism (as exemplified explicitly in Watson and Skinner, and implicitly in the computer-metaphorical, information-processing explanations employed by current "cognitive" psychology). A common feature of the metaphysical approach is that individual-differences variables like sex are essentially ignored, or relegated to ideological categories such as the treatment of sex as merely a "social construction." Examples of research both before and after the "cognitive revolution" are presented where experimental and differential methods are melded, and individual differences are treated as phenomena worthy of investigation rather than as nuisance factors that merely add to experimental error.

Animals↗
PubMed2003

Levinas, justice and health care.

In this paper I argue that the metaphysical ethics of Emmanuel Levinas captures some essential moral intuitions that are central to health care. However, there is an ongoing discussion about the relevance of ethical metaphysics for normative ethics and in particular on the question of the relationship between justice and individualized care. In this paper I take part in this debate and I argue that Levinas' idea of an ethics of the Other that guides politics and justice can shed important light on issues that are central to priorities in health care. In fact, the ethics of Levinas in seeking the foundation of normativity itself, captures the ethical core and central values of health care.

Delivery of Health Care↗
PubMed2003

It happens when the stage sets collapse.

Sally Gadow's tenure as professor of nursing at the University of Colorado Health Sciences Center during my doctoral studies radically changed my view on science, nursing, relationships, and most importantly, the world. In this paper, I use ideas stimulated by Gadow's classes to argue that recognizing ambiguity through an attitude of metaphysical revolt can free nurses to form relationships with patients who are complex subjects rather than objects to be treated. I will first discuss Camus' ideas of absurdity from the Myth of Sisyphus, comparing the awake passions of Don Juan and the maniacal (and fatal) love of Romeo and Juliet (1955). Merleau-Ponty's (1962) work on the dialectic of human sexuality sheds light on the intrinsic bodily ambiguity of human existence as seen through sexual attraction. de Beauvoir (1948) further lends insight into ideas of ambiguity, relationship, and freedom. Finally, I will argue that recognition of the intrinsic ambiguity of existence coupled with an attitude of metaphysical revolt may free nurses and patients from external frameworks that limit experience, impose meaning, and in the process, sever human relationship.

Ethics↗
PubMed2002

A phenomenographic approach to the meaning of death: a Chinese perspective.

The purpose of this study was to investigate qualitative and quantitative differences in Chinese children's concepts of death, as reflected in their drawings, and to analyze this conceptual development as it related to background variables (such as gender, age, religious belief, and heath status). Participants were 239 children in 6 grade groups recruited from primary and junior high school. The children were asked to draw their impression of the word "death" and to give a verbal commentary of what they had drawn. The drawings were analyzed according to a phenomenographic method and assigned to one of 3 superordinate and 12 subordinate qualitative categories, adapted from M. E.Tamm and A. Granqvist (1995). Metaphysical and biological death concepts dominated, while psychological death concepts were depicted least. Consistent with previous studies of the development of concepts of death in children, biological death concepts were most common for the younger age groups, and metaphysical death concepts were found predominately in the older age groups. Chi-square analysis revealed no significant differences among death concept categories as a function of the participants' gender, health status, religious belief, funeral attendance, or prior death of relatives or pets. The results are interpreted as providing a unique window on death concepts among Chinese children.

Adolescent↗
PubMed2004

Homosexuality, ethics and identity synthesis.

Implicit metaphysical assumptions concerning the nature of sexual orientation are reflected in the language used to frame ethical debates concerning "reorientation" therapies. An alternative metaphysical construal is presented concerning sexual orientation and sexual identity development and synthesis. This alternative construal allows for humility concerning what we know and do not know about sexual orientation, underscores the client's self-determination and autonomy, and demonstrates regard for personal and religious valuative frameworks. Rather than focusing on therapies aimed specifically at sexual reorientation, clinicians would do well to provide clients with informed consent and to facilitate identity development and synthesis in keeping with their clients' requests for professional services.

Behavior Therapy↗
PubMed2003

The bioethical structure of a human being.

Bioethical debates such as those surrounding the manipulation of human embryos are often based on metaphysical assumptions that lack a foundation in the natural sciences. In this paper we support a gradualist position whereby the embryo progressively takes on the form and associated ethical significance of a human being. We support this position by introducing a concept of biological structure or form to show how the gradualist position has its metaphysical foundations in modern biology. The conceptual basis for form and structure are outlined and their compatibility with and basis in current empirical biology is demonstrated by some recent advances in our understanding of the processes of development from single cell to organism. We then briefly explore the ethical significance of accepting a form or structure based conception of biology for the status of the early embryo.

Beginning of Human Life↗
PubMed1986

Philosophy of science and DSM-III. Philosophical, idea-historical and sociological perspectives on diagnoses.

The validity of a classification system is primarily a question of philosophical premise. DSM-III is from this point of view a theoretical classification system based on hypotheses currently considered reliable and interesting and which--as presupposed--could not be rejected by empirical methods. The relevance or validity of this empirical approach depends on the aim of the DSM-III. An empirical approach may facilitate communication but can only have limited success as a help for planning treatment of psychiatric disorders where motives and meaning are important factors. The choice of hypotheses and the empirically derived concepts used to construct the classification system neglects other important ways of comprehension. Although aspects of rational philosophy may be found in the DSM-III system too, important ways of comprehension like the metaphysical approach is lacking. It is showed how this fact reflects a philosophical trend in the Western world following the Renaissance. By considering the Myth of Faust it is demonstrated how a metaphysical comprehension of life would lead to a different understanding of states of mind currently assumed to be a reflection of individual psychopathology according to empirical or rational comprehension. Thus in the end the validity of a classification system depends on the basic philosophical assumptions chosen. A choice which may be determined more by irrational and cultural forces than conscious contemplation. The content of DSM-III or ICD is also influenced by professional interests; the needs of the society and international political factors.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗
PubMed2001

Understanding the universe.

Physics constrains metaphysics but does not determine it. The central metaphysical question is that of scope; a true theory of everything must take personal experience as seriously as the impersonal. Science raises questions of intelligibility and anthropic fine-tuning that go beyond its own self-limited power to answer. Theism provides a coherent response, as well as furnishing a foundation for the human encounter with value. Evolutionary insight affords some insight in relation to problems of physical evil, but eventual cosmic futility can only find an answer in the faithfulness of a Creator whose purposes are not frustrated by death.

Biological Evolution↗
PubMed1988

Resolving arguments about the sanctity of life: a response to Long.

Thomas Long has argued that there is an irreconcilable metaphysical difference between the views of those who, like ourselves, believe that on quality-of-life grounds it is sometimes justifiable to end the life of a severely handicapped infant, and those who, like Paul Ramsey, reject this view. Because of this metaphysical difference, Long considers it impossible for our arguments to refute Ramsey's position. We disagree.

Persons with Disabilities↗